[media] media: Use strlcpy instead of custom code

Replace strncpy + manually setting the terminating '\0' with an strlcpy
call.

Reported-by: Joe Perches <joe@perches.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>